[andykao]

So i'm trying to diagnose some boost issues and i'm having some problems. Bought the car in winter, changed BPC valve, cleaned MAF, got new spark plugs and DIC and the car was boosting fine. Hot weather came and i started having boost issues. Sometimes it would boost, sometimes it would not (most of the cases). I only got something around base boost when it was really hot outside - actually something a bit better than base boost, around 0.5 - 0.6 bar (sometimes 0.7).

I have opensid, no errors, running 99 octane fuel. Temperature gauge is stable (pointing all the time at 9 oclock, even when it's really hot outside - so fans / engine cooling works fine).

Cooler weather is here (especially in the evenings) and the car boost great, i'm able to reach 1000+ mair (could not reach more then 700-800 before).

It's clearly a temperature issue, but i was under the impression that the car should be able to do a a few good pulls even when it's hot outside (i can't do a single full boost pull when it's hot).

Any causes for this or things i should look for?

 

[Mimmi]

Do you have original air intake system?

 

[ivatigoal]

Do you have any way to test the intake air temp? After that you should try to bypass the wastegate but be careful of you it boosts do not over do it. If it boosts you know something is wrong with the wastegate or the solenoid.

 

[andykao]

i tried removing the wastegate hose from the bpc and it boosts fine (no matter how hot the temp is). i can hit fuel cut almost immediately. i don't believe it's the wastegate or bpc, as it all works fine when the weather is a bit cooler...

 

[Flash635]

About the temp gauge. They're not always spot on, when I was having trouble with various hose leaks and eventually a second radiator replacement I found that even if the gauge is reading good that I'd get some pinging and hesitation - signs of overheating.
When I finally got all the hoses sorted and a new radiator fitted it ran great for a long time but because my wife was driving it the water wasn't checked properly.
I checked it the other day and it needed nearly 2 litres but the gauge was reading normal.

I think the way the gauge reads can be adjusted using Tech 2.
That is it can read normal until the engine is slagged then the needle will pop up to tell you why you're not driving. You can then adjust it to read more sensibly.

 

[lms]

Do you have an OEM Dic? There are few threads that mention boost is fine until car gets hot, then boost sucks. Users replaced Dic, fixed.
Can it be cold out, but engine is hot and it works fine?

 

[andykao]

OEM DIC, made in Sweden by SEM